Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg.,
1990,17606,18135,18251,17671,16783,17590,17146,17792,16798,16436,17030,15519,17222,
1991,16327,17345,16970,18569,17398,17740,18576,24501,29632,28728,28240,27786,21836,
1992,29175,23893,19272,20298,18317,19904,18584,18209,20650,20591,19073,18681,20598,
1993,18026,20499,20514,22170,20378,20857,19578,19598,21128,20302,19789,20371,20258,
1994,19959,21598,22081,22149,20726,21587,19237,20752,22304,22034,21100,20010,21117,
1995,20546,22216,22793,23268,21540,22196,20158,21477,22705,23121,21363,20161,21795,
1996,20448,22321,22202,23363,19201,19350,18888,20416,22299,21759,21253,19149,20887,
1997,19405,21692,21451,22892,21342,20788,19020,20290,22514,22329,21353,19631,21059,
1998,19271,21864,21797,23159,20727,21107,19252,20495,21974,21952,20356,19475,20952,
1999,19518,21272,21501,22603,20858,21076,19194,20618,21763,22083,20663,19347,20875,
2000,19616,23587,23405,22618,20823,21599,19762,20100,21703,22145,20723,19623,21309,
2001,19436,21493,21412,22482,20039,19923,18606,19861,20887,21145,20062,18231,20298,
2002,18780,20359,19571,21499,19520,18681,17578,18687,20228,20793,19174,18294,19430,
2003,18954,20243,19242,21098,19460,19524,18371,18763,21269,21282,18985,18583,19648,
2004,18620,20283,20764,21681,19252,18921,17969,19302,21500,20891,19922,18493,19800,
2005,19075,20655,20571,21478,19333,19284,18133,20635,,21144,19881,18428,,
2006,18851,21100,20702,21278,20579,19203,18186,22243,,,21652,18150,,
2007,19246,21151,20827,21602,21606,,18881,19811,17576,22467,20524,18429,,
2008,17927,20914,19800,21612,19743,18224,17474,18195,,19591,18182,17205,,
2009,16922,19597,18919,20666,18317,17620,17548,,,19601,17914,17194,,
2010,16733,19813,19736,,17855,17883,17508,,20858,19674,17978,17489,,
2011,17819,19518,20288,20600,18231,17587,16871,18450,20657,18462,19067,16733,18690,
2012,16864,18187,,20085,,,17524,18469,21343,,18695,17650,18685,
2013,14884,,19904,19515,18127,17107,15704,16489,20488,19899,18207,16989,,
2014,16227,19352,19330,20736,19113,17926,17504,18624,20352,20464,17891,17966,18790,
2015,18132,20140,19711,21022,19211,18995,18554,19381,21123,20949,19133,18560,19576,
2016,22615,24708,23760,25439,23365,22479,22143,23815,22131,21202,19151,17532,22362,
2017,18112,20290,20333,21719,19527,19595,18044,20184,21411,21628,19508,18208,19880,
2018,19277,20476,20505,21939,20122,19807,18841,20251,22237,20529,18623,16994,19967,
2019,17815,19517,19568,21368,19635,18419,17639,18783,20017,20618,33819,25836,21086,
2020,17567,29155,21330,17536,11762,14538,12951,14663,16799,18528,12985,12016,16653,
2021,13215,14302,15657,15767,15732,15520,13830,15594,16441,16207,14517,13585,15031,
2022,13349,15088,15690,16568,15790,15358,14871,16506,17321,17314,14793,13253,15492,
2023,14306,15292,15182,16805,16265,15780,14989,16609,16616,17086,15102,14033,15672,
2024,13612,15869,15542, , , , , , , , , , ,